Air cleaners and purifiers are widely used for removing foreign substances from air. The foreign substances can include pollen, dander, smoke, pollutants, dust, etc. In addition, an air cleaner can be used to circulate room air. An air cleaner can be used in many settings, including at home, in offices, etc.
One type of air cleaner is an electrostatic precipitator. An electrostatic precipitator operates by creating an electrical field. Dirt and debris in the air becomes ionized when it is brought into the electrical field by an airflow. Charged positive and negative electrodes in the electrostatic precipitator air cleaner, such as positive and negative plates or positive and grounded plates, create the electrical field and one of the electrode polarities attracts the ionized dirt and debris. Periodically, the electrostatic precipitator can be removed and cleaned. Because the electrostatic precipitator comprises electrodes or plates through which airflow can easily and quickly pass, only a low amount of energy is required to provide airflow through the electrostatic precipitator. As a result, foreign objects in the air can be efficiently and effectively removed without the need for a mechanical filter element. However, the prior art electrostatic precipitator element offers a limited distance of airflow travel over which to ionize and remove dirt and debris entrained in the airflow.
FIG. 1 shows a prior art electrostatic precipitator 100 that includes an electrostatic precipitator cell 101 and a pre-ionizer stage 120. The prior art electrostatic precipitator cell 101 includes charge plates 102 that are electrically connected to a voltage source 104 and grounded collection plates 103. The charge plates 102 and the collection plates 103 are substantially parallel and spaced-apart, wherein airflow can move between the plates. The prior art pre-ionizer 120 comprises corona charge elements 126 located in the airflow before (i.e., in front of) the charge plates 102 and the collection plates 103. The corona charge elements 126 are typically aligned with or are co-planar with the charge plates 102. In the prior art the corona charge elements 126 are energized by the same voltage source 104 as the charge plates 102 and at the same voltage potential. The pre-ionizer 120 at least partially ionizes the airflow and the entrained particulate before the airflow enters the electrostatic precipitator cell 101, thereby increasing the particulate-removing efficiency of the prior art electrostatic precipitator 100.
A drawback of the prior art pre-ionizer 120 is that the pre-ionizing electrical field is created behind/downstream of the corona charge elements 126 and between the corona charge elements 126 and the collection plates 103. As a result, regions of the airflow may be only partly or minimally pre-ionized. Another drawback is that in the prior art, the voltage potential on the corona charge elements 126 is typically the same voltage level as the charge plates 102 (i.e., the prior art corona charge elements 126 are attached to or in contact with the charge plates 102). The ionization level of the prior art pre-ionizer 120 may therefore be only as effective and efficient as the ionization created by the charge plates 102 and the collection plates 103 of the prior art electrostatic precipitator 100.
FIG. 17 shows a prior art corona wire loop end of a corona wire used in a prior art electrostatic precipitator. The prior art corona wire loop end is crimped onto the prior art corona wire, and slips over some manner of tongue or tab of the prior art electrostatic precipitator during assembly.
However, the prior art corona wire and prior art corona wire loop end have drawbacks. The prior art corona wire loop end is relatively complicated in design and therefore costly to manufacture. The prior art corona wire loop end can slip off of the corresponding tab if too much tension is placed on the prior art corona wire. The prior art corona wire loop end includes unnecessary structure. The prior art corona wire loop end is relatively wide, and introduces a possibility of arcing to adjacent components when a high voltage is placed on the prior art corona wire.